A high-stakes legal battle between Elon Musk and OpenAI chief executive Sam Altman is underway at a federal courthouse in Oakland, California, in a case centred on whether OpenAI's transformation from a non-profit into a commercial entity — now potentially worth up to $1 trillion ahead of a possible IPO — betrayed its founding mission. Musk, who co-founded OpenAI (the artificial intelligence research organisation behind ChatGPT) in 2015, took the stand this week to argue that the pivot violated the charitable purpose he says underpinned the original venture; OpenAI counters that Musk is a disgruntled former partner seeking to hobble a rival. Beyond the personal rivalry, the case raises a landmark question for the tech industry: whether a commitment to develop powerful AI for humanity's benefit remains legally binding once that technology becomes extraordinarily profitable.